Area management of tissue sites on articulating joints

ABSTRACT

A dressing for managing an incision and surrounding tissue where edema and swelling may be present post-operation. The dressing may maximize coverage of area in articulating joints, such as a knee or elbow, while allowing for substantial range of motion. In some embodiments, the dressing may comprise an adhesive border configured to be adhered to skin around an articulating joint, a skin-interfacing fabric for minimizing skin irritation, a foam body for manifolding negative pressure and absorbing exudate and other body fluids, and a thin polymer film cap for sealing the assembly so negative pressure can be maintained throughout the dressing.

RELATED APPLICATION

This present invention claims the benefit, under 35 USC 119(e), of thefiling of U.S. Provisional Patent Application Ser. No. 62/575,961,entitled “Area Management of Tissue Sites on Articulating Joints”, filedOct. 23, 2017, and is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The invention set forth in the appended claims relates generally totissue treatment systems and more particularly, but without limitation,to area management of incisions and other tissue sites on articulatingjoints.

BACKGROUND

Clinical studies and practice have shown that reducing pressure inproximity to a tissue site can augment and accelerate growth of newtissue at the tissue site. The applications of this phenomenon arenumerous, but it has proven particularly advantageous for treatingwounds. Regardless of the etiology of a wound, whether trauma, surgery,or another cause, proper care of the wound is important to the outcome.Treatment of wounds or other tissue with reduced pressure may becommonly referred to as “negative-pressure therapy,” but is also knownby other names, including “negative-pressure wound therapy,”“reduced-pressure therapy,” “vacuum therapy,” “vacuum-assisted closure,”and “topical negative-pressure,” for example. Negative-pressure therapymay provide a number of benefits, including migration of epithelial andsubcutaneous tissues, improved blood flow, and micro-deformation oftissue at a wound site. Together, these benefits can increasedevelopment of granulation tissue and reduce healing times.

While the clinical benefits of negative-pressure therapy are widelyknown, improvements to therapy systems, components, and processes maybenefit healthcare providers and patients.

BRIEF SUMMARY

New and useful systems, apparatuses, and methods for managing tissuesites in a negative-pressure therapy environment are set forth in theappended claims. Illustrative embodiments are also provided to enable aperson skilled in the art to make and use the claimed subject matter.

For example, such an apparatus may be a dressing for managing anincision and surrounding tissue where edema and swelling may be presentpost-operation. The dressing may maximize coverage of area inarticulating joints, such as a knee or elbow, while allowing forsubstantial range of motion. In some embodiments, the dressing maycomprise an adhesive border configured to be adhered to skin around anarticulating joint, a skin-interfacing fabric for minimizing skinirritation, a foam body for manifolding negative pressure and absorbingexudate and other body fluids, and a thin polymer film cap for sealingthe assembly so negative pressure can be maintained throughout thedressing. In some embodiments, the dressing may have one or moreportions which can be cut to customize the size of the dressing.Separate adhesive films can be applied over the cut portions forsealing.

More generally, a dressing for treating an area around an articulatingjoint may comprise an attachment device, such as a sealing ring, havinga treatment aperture; a manifold comprising a stem, a first arm joinedto the stem, and a second arm joined to the stem; a cover disposed overthe manifold and coupled to the attachment device around the manifold;and an adhesive on the attachment device configured to bond to the areaaround the articulating joint. The manifold may be at least partiallyexposed through the treatment aperture.

In some embodiments, the manifold may comprise a first arm having agreater span than the second arm. The first arm and the second arm mayflare away from the stem in some embodiments. The manifold may comprisea face that is biconcave in some embodiments. For example, the stem, thefirst arm, and the second arm may define a concave void on opposingsides of the manifold.

Other aspects of the dressing may comprise a manifold having a firstportion configured to be disposed over an articulating surface of alimb; a second portion configured to be at least partially wrappedaround a proximal portion of the limb; and a third portion configured tobe at least partially wrapped around a distal portion of the limb. Forexample, the first portion may be positioned over a knee. The dressingmay have an opening or void on each side of the first portion betweenthe second portion and the third portion. In some aspects, the secondportion and the third portion may have converging edges. In someaspects, the second portion and the third portion may flare away from amidline of the first portion.

An example method of treating an area around an articulating joint of alimb may comprise applying the dressing so that a stem of the dressingis disposed over the articulating joint; wrapping a first arm of thedressing around a proximal portion of the limb; wrapping a second armaround a distal portion of the limb; fluidly coupling anegative-pressure source to the manifold; and applying negative-pressurefrom the negative-pressure source.

Objectives, advantages, and a preferred mode of making and using theclaimed subject matter may be understood best by reference to theaccompanying drawings in conjunction with the following detaileddescription of illustrative embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram of an example embodiment of atherapy system that can provide negative-pressure treatment inaccordance with this specification;

FIG. 2 is a graph illustrating additional details of example pressurecontrol modes that may be associated with some embodiments of thetherapy system of FIG. 1;

FIG. 3 is a graph illustrating additional details that may be associatedwith another example pressure control mode in some embodiments of thetherapy system of FIG. 1;

FIG. 4 is a top view of a dressing illustrating additional details thatmay be associated with an example embodiment of therapy system of FIG.1;

FIG. 5 is an assembly view of the dressing of FIG. 4, illustratingadditional details that may be associated with some examples;

FIG. 6 is a top view of another example of the dressing, illustratingadditional details that may be associated with some embodiments; and

FIG. 7 illustrates the dressing of FIG. 4 applied to an articulatingjoint.

DESCRIPTION OF EXAMPLE EMBODIMENTS

The following description of example embodiments provides informationthat enables a person skilled in the art to make and use the subjectmatter set forth in the appended claims, but may omit certain detailsalready well-known in the art. The following detailed description is,therefore, to be taken as illustrative and not limiting.

The example embodiments may also be described herein with reference tospatial relationships between various elements or to the spatialorientation of various elements depicted in the attached drawings. Ingeneral, such relationships or orientation assume a frame of referenceconsistent with or relative to a patient in a position to receivetreatment. However, as should be recognized by those skilled in the art,this frame of reference is merely a descriptive expedient rather than astrict prescription.

FIG. 1 is a simplified functional block diagram of an example embodimentof a therapy system 100 that can provide negative-pressure therapy to atissue site in accordance with this specification.

The term “tissue site” in this context broadly refers to a wound,defect, or other treatment target located on or within tissue, includingbut not limited to, bone tissue, adipose tissue, muscle tissue, neuraltissue, dermal tissue, vascular tissue, connective tissue, cartilage,tendons, or ligaments. A wound may include chronic, acute, traumatic,subacute, and dehisced wounds, partial-thickness burns, ulcers (such asdiabetic, pressure, or venous insufficiency ulcers), flaps, and grafts,for example. The term “tissue site” may also refer to areas of anytissue that are not necessarily wounded or defective, but are insteadareas in which it may be desirable to add or promote the growth ofadditional tissue. For example, negative pressure may be applied to atissue site to grow additional tissue that may be harvested andtransplanted.

The therapy system 100 may include a source or supply of negativepressure, such as a negative-pressure source 105, a dressing 110, afluid container, such as a container 115, and a regulator or controller,such as a controller 120, for example. Additionally, the therapy system100 may include sensors to measure operating parameters and providefeedback signals to the controller 120 indicative of the operatingparameters. As illustrated in FIG. 1, for example, the therapy system100 may include one or more sensors coupled to the controller 120, suchas a first sensor 125 and a second sensor 130. As illustrated in theexample of FIG. 1, the dressing 110 may comprise or consist essentiallyof a tissue interface 135, a cover 140, or both in some embodiments.

Some components of the therapy system 100 may be housed within or usedin conjunction with other components, such as sensors, processing units,alarm indicators, memory, databases, software, display devices, or userinterfaces that further facilitate therapy. For example, in someembodiments, the negative-pressure source 105 may be combined with thecontroller 120 and other components into a therapy unit.

In general, components of the therapy system 100 may be coupled directlyor indirectly. For example, the negative-pressure source 105 may bedirectly coupled to the container 115, and may be indirectly coupled tothe dressing 110 through the container 115. Coupling may include fluid,mechanical, thermal, electrical, or chemical coupling (such as achemical bond), or some combination of coupling in some contexts. Forexample, the negative-pressure source 105 may be electrically coupled tothe controller 120, and may be fluidly coupled to one or moredistribution components to provide a fluid path to a tissue site. Insome embodiments, components may also be coupled by virtue of physicalproximity, being integral to a single structure, or being formed fromthe same piece of material.

A distribution component is preferably detachable, and may bedisposable, reusable, or recyclable. The dressing 110 and the container115 are illustrative of distribution components. A fluid conductor isanother illustrative example of a distribution component. A “fluidconductor,” in this context, broadly includes a tube, pipe, hose,conduit, or other structure with one or more lumina or open pathwaysadapted to convey a fluid between two ends. Typically, a tube is anelongated, cylindrical structure with some flexibility, but the geometryand rigidity may vary. Moreover, some fluid conductors may be moldedinto or otherwise integrally combined with other components.Distribution components may also include or comprise interfaces or fluidports to facilitate coupling and de-coupling other components. In someembodiments, for example, a dressing interface may facilitate coupling afluid conductor to the dressing 110. For example, such a dressinginterface may be a SENSAT.R.A.C.™ Pad available from KCI of San Antonio,Tex.

A negative-pressure supply, such as the negative-pressure source 105,may be a reservoir of air at a negative pressure, or may be a manual orelectrically-powered device, such as a vacuum pump, a suction pump, awall suction port available at many healthcare facilities, or amicro-pump, for example. “Negative pressure” generally refers to apressure less than a local ambient pressure, such as the ambientpressure in a local environment external to a sealed therapeuticenvironment. In many cases, the local ambient pressure may also be theatmospheric pressure at which a tissue site is located. Alternatively,the pressure may be less than a hydrostatic pressure associated withtissue at the tissue site. Unless otherwise indicated, values ofpressure stated herein are gauge pressures. References to increases innegative pressure typically refer to a decrease in absolute pressure,while decreases in negative pressure typically refer to an increase inabsolute pressure. While the amount and nature of negative pressureapplied to a tissue site may vary according to therapeutic requirements,the pressure is generally a low vacuum, also commonly referred to as arough vacuum, between −5 mm Hg (−667 Pa) and −500 mm Hg (−66.7 kPa).Common therapeutic ranges are between −50 mm Hg (−6.7 kPa) and −300 mmHg (−39.9 kPa).

The container 115 is representative of a container, canister, pouch, orother storage component, which can be used to manage exudates and otherfluids withdrawn from a tissue site. In many environments, a rigidcontainer may be preferred or required for collecting, storing, anddisposing of fluids. In other environments, fluids may be properlydisposed of without rigid container storage, and a re-usable containercould reduce waste and costs associated with negative-pressure therapy.

A controller, such as the controller 120, may be a microprocessor orcomputer programmed to operate one or more components of the therapysystem 100, such as the negative-pressure source 105. In someembodiments, for example, the controller 120 may be a microcontroller,which generally comprises an integrated circuit containing a processorcore and a memory programmed to directly or indirectly control one ormore operating parameters of the therapy system 100. Operatingparameters may include the power applied to the negative-pressure source105, the pressure generated by the negative-pressure source 105, or thepressure distributed to the tissue interface 135, for example. Thecontroller 120 is also preferably configured to receive one or moreinput signals, such as a feedback signal, and programmed to modify oneor more operating parameters based on the input signals.

Sensors, such as the first sensor 125 and the second sensor 130, aregenerally known in the art as any apparatus operable to detect ormeasure a physical phenomenon or property, and generally provide asignal indicative of the phenomenon or property that is detected ormeasured. For example, the first sensor 125 and the second sensor 130may be configured to measure one or more operating parameters of thetherapy system 100. In some embodiments, the first sensor 125 may be atransducer configured to measure pressure in a pneumatic pathway andconvert the measurement to a signal indicative of the pressure measured.In some embodiments, for example, the first sensor 125 may be apiezoresistive strain gauge. The second sensor 130 may optionallymeasure operating parameters of the negative-pressure source 105, suchas the voltage or current, in some embodiments. Preferably, the signalsfrom the first sensor 125 and the second sensor 130 are suitable as aninput signal to the controller 120, but some signal conditioning may beappropriate in some embodiments. For example, the signal may need to befiltered or amplified before it can be processed by the controller 120.Typically, the signal is an electrical signal, but may be represented inother forms, such as an optical signal.

The tissue interface 135 can be generally adapted to partially or fullycontact a tissue site. The tissue interface 135 may take many forms, andmay have many sizes, shapes, or thicknesses depending on a variety offactors, such as the type of treatment being implemented or the natureand size of a tissue site. For example, the size and shape of the tissueinterface 135 may be adapted to the contours of deep and irregularshaped tissue sites. Moreover, any or all of the surfaces of the tissueinterface 135 may have projections or an uneven, course, or jaggedprofile that can induce strains and stresses on a tissue site, which canpromote granulation at the tissue site.

In some embodiments, the tissue interface 135 may be a manifold. A“manifold” in this context generally includes any substance or structureproviding a plurality of pathways adapted to collect or distribute fluidacross a tissue site under pressure. For example, a manifold may beadapted to receive negative pressure from a source and distributenegative pressure through multiple apertures across a tissue site, whichmay have the effect of collecting fluid from across a tissue site anddrawing the fluid toward the source. In some embodiments, the fluid pathmay be reversed or a secondary fluid path may be provided to facilitatedelivering fluid across a tissue site.

In some illustrative embodiments, the pathways of a manifold may beinterconnected to improve distribution or collection of fluids across atissue site. In some illustrative embodiments, a manifold may be aporous foam material having interconnected cells or pores. For example,open-cell foam, porous tissue collections, and other porous materialsuch as gauze or felted mat generally include pores, edges, and/or wallsadapted to form interconnected fluid channels. Liquids, gels, and otherfoams may also include or be cured to include apertures and fluidpathways. In some embodiments, a manifold may additionally oralternatively comprise projections that form interconnected fluidpathways. For example, a manifold may be molded to provide surfaceprojections that define interconnected fluid pathways.

The average pore size of foam may vary according to needs of aprescribed therapy. For example, in some embodiments, the tissueinterface 135 may be foam having pore sizes in a range of 400-600microns. The tensile strength of the tissue interface 135 may also varyaccording to needs of a prescribed therapy. For example, the tensilestrength of foam may be increased for instillation of topical treatmentsolutions. In some examples, the tissue interface 135 may be reticulatedpolyurethane foam such as found in GRANUFOAM™ dressing or V.A.C.VERAFLO™ dressing, both available from KCI of San Antonio, Tex.

The tissue interface 135 may be either hydrophobic or hydrophilic. In anexample in which the tissue interface 135 may be hydrophilic, the tissueinterface 135 may also wick fluid away from a tissue site, whilecontinuing to distribute negative pressure to the tissue site. Thewicking properties of the tissue interface 135 may draw fluid away froma tissue site by capillary flow or other wicking mechanisms. An exampleof hydrophilic foam is a polyvinyl alcohol, open-cell foam such asV.A.C. WHITEFOAM™ dressing available from KCI of San Antonio, Tex. Otherhydrophilic foams may include those made from polyether. Other foamsthat may exhibit hydrophilic characteristics include hydrophobic foamsthat have been treated or coated to provide hydrophilicity.

The tissue interface 135 may further promote granulation at a tissuesite when pressure within the sealed therapeutic environment is reduced.For example, any or all of the surfaces of the tissue interface 135 mayhave an uneven, coarse, or jagged profile that can induce microstrainand stress at a tissue site if negative pressure is applied through thetissue interface 135.

In some embodiments, the tissue interface 135 may be constructed frombioresorbable materials. Suitable bioresorbable materials may include,without limitation, a polymeric blend of polylactic acid (PLA) andpolyglycolic acid (PGA). The polymeric blend may also include withoutlimitation polycarbonates, polyfumarates, and capralactones. The tissueinterface 135 may further serve as a scaffold for new cell-growth, or ascaffold material may be used in conjunction with the tissue interface135 to promote cell-growth. A scaffold is generally a substance orstructure used to enhance or promote the growth of cells or formation oftissue, such as a three-dimensional porous structure that provides atemplate for cell growth. Illustrative examples of scaffold materialsinclude calcium phosphate, collagen, PLA/PGA, coral hydroxy apatites,carbonates, or processed allograft materials.

In some embodiments, the cover 140 may provide a bacterial barrier andprotection from physical trauma. The cover 140 may also be constructedfrom a material that can reduce evaporative losses and provide a fluidseal between two components or two environments, such as between atherapeutic environment and a local external environment. For example,the cover 140 may comprise or consist essentially of an elastomeric filmor membrane that can provide a seal adequate to maintain a negativepressure at a tissue site for a given negative-pressure source. In someexample embodiments, the cover 140 may be a polymer drape, such as apolyurethane film, that is permeable to water vapor but impermeable toliquid. The cover 140 may have a high moisture-vapor transmission rate(MVTR) in some applications. For example, the MVTR may be at least 250g/m^(∧)2 per twenty-four hours in some embodiments (based on ASTME96/E96M for upright cup measurement). Such drapes typically have athickness in the range of 25-50 microns. For permeable materials, thepermeability generally should be low enough that a desired negativepressure may be maintained.

An attachment device may be used to attach the cover 140 to anattachment surface, such as undamaged epidermis, a gasket, or anothercover. The attachment device may take many forms. For example, anattachment device may be a medically-acceptable, pressure-sensitiveadhesive configured to bond the cover 140 to epidermis around a tissuesite. In some embodiments, for example, some or all of the cover 140 maybe coated with an adhesive, such as an acrylic adhesive, which may havea coating weight between 25-65 grams per square meter (g.s.m.). Thickeradhesives, or combinations of adhesives, may be applied in someembodiments to improve the seal and reduce leaks. Other exampleembodiments of an attachment device may include a double-sided tape,paste, hydrocolloid, hydrogel, silicone gel, or organogel.

FIG. 2 is a graph illustrating additional details of an example controlmode that may be associated with some embodiments of the controller 120.In some embodiments, the controller 120 may have a continuous pressuremode, in which the negative-pressure source 105 is operated to provide aconstant target negative pressure, as indicated by line 205 and line210, for the duration of treatment or until manually deactivated.Additionally or alternatively, the controller may have an intermittentpressure mode, as illustrated in the example of FIG. 2. In FIG. 2, thex-axis represents time, and the y-axis represents negative pressuregenerated by the negative-pressure source 105 over time. In the exampleof FIG. 2, the controller 120 can operate the negative-pressure source105 to cycle between a target pressure and atmospheric pressure. Forexample, the target pressure may be set at a value of 125 mmHg, asindicated by line 205, for a specified period of time (e.g., 5 min),followed by a specified period of time (e.g., 2 min) of deactivation, asindicated by the gap between the solid lines 215 and 220. The cycle canbe repeated by activating the negative-pressure source 105, as indicatedby line 220, which can form a square wave pattern between the targetpressure and atmospheric pressure.

In some example embodiments, the increase in negative-pressure fromambient pressure to the target pressure may not be instantaneous. Forexample, the negative-pressure source 105 and the dressing 110 may havean initial rise time, as indicated by the dashed line 225. The initialrise time may vary depending on the type of dressing and therapyequipment being used. For example, the initial rise time for one therapysystem may be in a range of about 20-30 mmHg/second and in a range ofabout 5-10 mmHg/second for another therapy system. If the therapy system100 is operating in an intermittent mode, the repeating rise time asindicated by the solid line 220 may be a value substantially equal tothe initial rise time as indicated by the dashed line 225.

FIG. 3 is a graph illustrating additional details that may be associatedwith another example pressure control mode in some embodiments of thetherapy system 100. In FIG. 3, the x-axis represents time and the y-axisrepresents negative pressure generated by the negative-pressure source105. The target pressure in the example of FIG. 3 can vary with time ina dynamic pressure mode. For example, the target pressure may vary inthe form of a triangular waveform, varying between a minimum and maximumnegative pressure of 50-125 mmHg with a rise time 305 set at a rate of+25 mmHg/min. and a descent time 310 set at −25 mmHg/min, respectively.In other embodiments of the therapy system 100, the triangular waveformmay vary between negative pressure of 25-125 mmHg with a rise time 305set at a rate of +30 mmHg/min and a descent time 310 set at −30mmHg/min.

In some embodiments, the controller 120 may control or determine avariable target pressure in a dynamic pressure mode, and the variabletarget pressure may vary between a maximum and minimum pressure valuethat may be set as an input prescribed by an operator as the range ofdesired negative pressure. The variable target pressure may also beprocessed and controlled by the controller 120, which can vary thetarget pressure according to a predetermined waveform, such as atriangular waveform, a sine waveform, or a saw-tooth waveform. In someembodiments, the waveform may be set by an operator as the predeterminedor time-varying negative pressure desired for therapy.

FIG. 4 is a top view of an example of the dressing 110, illustratingadditional details that may be associated with some embodiments. In theexample embodiment of FIG. 4, the dressing 110 includes features thatcan cover articulating joints, such as a knee, while still allowing forsignificant range of motion. For example, the dressing 110 of FIG. 4generally comprises a manifold 405 having a stem 410, a first arm 415joined to a first end of the stem 410, and a second arm 420 joined to asecond end of the stem 410.

In some embodiments, the manifold 405 may be characterized as apolyhedron or as a generalized cylinder. For example, in FIG. 4 themanifold 405 can be characterized as a generalized cylinder having aface 425 and an edge 430. The edge 430 in FIG. 4 bounds the stem 410,the first arm 415, and the second arm 420. In some embodiments, someportions of the edge 430 may be curved, and some portions may bestraight. In FIG. 4, for example, the first arm 415 is bounded in partby a first edge portion 435 that is substantially straight, and thesecond arm 420 is bounded in part by a second edge portion 440 that issubstantially straight. In other embodiments, the first arm 415, thesecond arm 420, or both may be contoured at the extremities.

The stem 410 is generally configured to be positioned over an articularsurface. The width of the stem 410 may vary for different types ofjoints, and may be limited to minimize interference with articulation.For example, in some embodiments, the stem 410 may be configured forpositioning over a patella and have a width of 2-4 inches. In otherexamples, a width of 1-3 inches may be suitable for positioning over anolecranon.

As illustrated in the example of FIG. 4, the first arm 415 and thesecond arm 420 may flare away from the stem 410. In some examples, theface 425 may be biconcave. More generally, portions of the edge 430bounding the first arm 415 and the second arm 420 may converge towardthe stem 410 to define a concave void adjacent to each side of the stem410. In the example of FIG. 4, the concave void is curved. In otherexamples, the edge 430 may have straight segments that converge toward avertex at the stem 410.

Some embodiments of the manifold 405 may additionally be characterizedby a line of symmetry 445 through the stem 410, and each of the firstarm 415 and the second arm 420 may be characterized by a span that isgenerally orthogonal to the line of symmetry 445. In the example of FIG.4, a first span 450 between extremities 455 is characteristic of thefirst arm 415, and a second span 460 between extremities 465 ischaracteristic of the second arm 420.

In the example of FIG. 4, the first span 450 is greater than the secondspan 460. A suitable ratio of the span of the first span 450 to thesecond span 460 may generally be in a range of 1.2 to 3.4. A ratio of1.2 to 1.6 may be particularly advantageous for some applications. Forexample, in some embodiments the first span 450 may be in a range of30-65 centimeters and the second span 460 may be in a range of 20-45centimeters. In other examples, the first span 450 may be in a range of15-50 centimeters and the second span 460 may be in a range of 8-25centimeters.

In some embodiments, a fluid conductor 470 may be coupled to thedressing 110. As illustrated in FIG. 4, the fluid conductor 470 may becoupled to the first arm 415. FIG. 4 also illustrates an example of adressing interface 475 that may be used to facilitate fluidly couplingthe fluid conductor 470 to the manifold 405.

FIG. 5 is an assembly view of the dressing 110 of FIG. 4, illustratingadditional details that may be associated with some examples. In theexample of FIG. 5, the cover 140, the manifold 405, an adhesive ring505, and an attachment device 510 with a treatment area aperture 515 aredisposed in a stacked relationship. In general, the cover 140, themanifold 405, the adhesive ring 505, and the attachment device 510 ofFIG. 5 have similar shapes. The attachment device 510 may be slightlylarger than the manifold 405, and the adhesive ring 505 can bond aperipheral portion of the manifold 405 to an interior portion of theattachment device 510. The manifold 405 can be exposed through thetreatment area aperture 515. In some embodiments, an adhesive may bedisposed on at least portions of the manifold 405 exposed through thetreatment area aperture 515. For example, portions of the first arm 415,the second arm 420, or both may have an adhesive coating. In someembodiments, the adhesive may be pattern-coated, and may cover up to 50%of the surface. The dressing 110 may optionally include one or morerelease liners, such as a center release liner 520, a first side releaseliner 525, and a second side release liner 530. In some examples, thedressing 110 may have two release liners, each of which may haveperforations or slits configured to allow the release liners to beseparated into smaller pieces for removal. Additionally, someembodiments may also have one or more casting sheet liners 535.

In some embodiments, the attachment device 510 may be a sealing ring.Similar or analogous to the cover 140, a suitable sealing ring may be,for example, an elastomeric film or membrane that can provide a seal ina therapeutic negative-pressure environment. In some exampleembodiments, the attachment device 510 may be a polymer film, such as apolyurethane film, that is permeable to water vapor but impermeable toliquid. The attachment device 510 typically has a thickness in the rangeof 25-50 microns. For permeable materials, the permeability generallyshould be low enough that a desired negative pressure may be maintained.The attachment device 510 may also include a medically-acceptable,pressure-sensitive adhesive. In some embodiments, for example, theattachment device 510 may be a polymer film coated with an adhesive,such as an acrylic adhesive, which may have a coating weight between25-65 grams per square meter (g.s.m.). Thicker adhesives, orcombinations of adhesives, may be applied in some embodiments to improvethe seal and reduce leaks. Additionally or alternatively, the attachmentdevice 510 may comprise a hydrocolloid adhesive, which can substantiallyreduce or prevent skin irritation.

As illustrated in the example of FIG. 5, some embodiments of themanifold 405 may have flexibility notches 540. The flexibility notches540 may be parallel to the line of symmetry 445, perpendicular to theline of symmetry 445, or both. Additionally or alternatively, one ormore of the flexibility notches 540 may be oblique to the line ofsymmetry 445. In some embodiments, only the stem 410 may have theflexibility notches 540. In other embodiments, only the first arm 415,the second arm 420, or both may have the flexibility notches 540.

The thickness of the manifold 405 may vary according to prescribedtherapy. In some embodiments, the manifold 405 or some portion of themanifold 405 may comprise felted, open-cell foam to increase rigidity.Additionally or alternatively, the manifold 405 may comprise foamsegments having different density. For example, the stem 410 maycomprise or consist essentially of open-cell foam having a higherdensity than the first arm 415 and the second arm 420.

The cover 140 may be larger than the manifold 405, as illustrated in theexample of FIG. 5, and may have a perimeter configured to be attached tothe attachment device 510. For example, the cover 140 may have a flange545. Assembled, the cover 140 may be disposed over the face 425, and theflange 545 may be attached to the attachment device 510 around themanifold 405. For example, an adhesive may be used to adhere the flange545 to the attachment device 510, or the flange 545 may be welded,stitched, or stapled to the attachment device 510. The cover 140 alsohas an aperture 550 and an expansion zone 555 in the example of FIG. 5.The aperture 550 can allow fluid communication between the manifold 405and a dressing interface or fluid conductor. The expansion zone 555 maycomprise folds, ribs, bellows, or other means for allowing the cover 140to expand if needed.

Some embodiments of the dressing 110 may additionally include a comfortlayer (not shown) coupled to the manifold and at least partially exposedthrough the treatment area aperture 515. The comfort layer may compriseor consist essentially of a material that substantially reduces oreliminates skin irritation while allowing fluid transfer through thecomfort layer. Examples of materials that may be suitable include wovenor non-woven textiles and fenestrated polymer films.

The center release liner 520, the first side release liner 525, and thesecond side release liner 530 may cover any adhesive on the attachmentdevice 510. Additionally or alternatively, the center release liner 520,the first side release liner 525, and the second side release liner 530may provide stiffness to the attachment device 510 to facilitatehandling and application. Additionally or alternatively, the castingsheet liners 535 may cover the flange 545 to provide stiffness to thecover 140 for handling and application.

FIG. 6 is a top view of another example of the dressing 110,illustrating additional details that may be associated with someembodiments. The dressing 110 of FIG. 6 is similar the dressing 110 ofFIG. 4 in many respects. For example, the face 425 of the dressing 110of FIG. 6 may be biconcave. More generally, portions of the edge 430bounding the first arm 415 and the second arm 420 may converge towardthe stem 410 to define a concave void adjacent to each side of the stem410.

The manifold 405 may additionally be characterized by a line of symmetry605 through the stem 410, and each of the first arm 415 and the secondarm 420 may be characterized by a span that is generally parallel to theline of symmetry 605. In the example of FIG. 6, the first span 450 andthe second span 460 are substantially equal. The stem 410 in the exampleof FIG. 6 is offset from a center of the first span 450 and the secondspan 460. Thus, the first arm 415 and the second arm 420 each have asacrificial extension portion 610 on one side of the stem 410.

In some embodiments, the manifold 405 may have distinct pressure zones.For example, the stem 410 may be fluidly isolated from the first arm415, the second arm 420, or both. Each pressure zone may have a distinctfluid interface in some embodiments.

The cover 140, the manifold 405, the attachment device 510, or variouscombinations may be assembled before application or in situ. In someembodiments, the dressing 110 may be provided as a single unit.

In use, the center release liner 520 may be removed from the dressing110, exposing a portion of the attachment device 510. The manifold 405may be placed within, over, on, or otherwise proximate to a tissue site,and the exposed portion of the attachment device 510 may be placedagainst epidermis adjacent to the tissue site. If the tissue site is anincision, for example, the manifold 405 may be placed over the incision.In some embodiments, the line of symmetry 445 may be aligned with someor all of the incision. If the tissue site is on a limb, the first arm415 may be wrapped around a proximal portion of the limb and the secondarm 420 may be wrapped around a distal portion of the limb. The firstarm 415 and the second arm 420 may not directly contact the incision insome applications, and a stronger adhesive may be used to secure atleast portions of the first arm 415 and the second arm 420 to epidermisadjacent to the incision. The first side release liner 525 and thesecond side release liner 530 may be removed and applied to additionalepidermis adjacent to the tissue site. Thus, the dressing 110 canprovide a sealed therapeutic environment proximate to a tissue site,substantially isolated from the external environment, and thenegative-pressure source 105 can be fluidly coupled to the manifold 405through the aperture 550.

FIG. 7 illustrates the dressing 110 of FIG. 4 applied to an incision(not shown) on an articulating joint. In the example of FIG. 7, thearticulating joint is a knee 705. As illustrated in the example of FIG.7, the stem 410 may substantially cover the top of the knee 705. Themanifold 405 is preferably oriented so that the first arm 415 and thefluid conductor 470 are superior to the knee 705. The first arm 415 maycover and wrap around a portion of the leg superior to the knee 705, andthe second arm 420 may cover and wrap around a portion of the leginferior to the knee 705. In some embodiments, one or more of the firstarm 415 and the second arm 420 may be cut to reduce the first span 450,the second span 460, or both. For example, in the dressing 110 of FIG.6, the extension portion 610 of the first arm 415, the second arm 420,or both may be cut so that the first arm 415 and the second arm 420 canfully wrap a portion of the leg superior and inferior to the knee 705,respectively.

In operation, the negative-pressure source 105 can reduce pressure inthe sealed therapeutic environment. Negative pressure applied across thetissue site through the manifold 405 in the sealed therapeuticenvironment can induce macro-strain and micro-strain in the tissue site,as well as remove exudates and other fluids from the tissue site, whichcan be collected in the container 115.

The fluid mechanics of using a negative-pressure source to reducepressure in another component or location, such as within a sealedtherapeutic environment, can be mathematically complex. However, thebasic principles of fluid mechanics applicable to negative-pressuretherapy are generally well-known to those skilled in the art, and theprocess of reducing pressure may be described illustratively herein as“delivering,” “distributing,” or “generating” negative pressure, forexample.

In general, exudates and other fluids flow toward lower pressure along afluid path. Thus, the term “downstream” typically implies something in afluid path relatively closer to a source of negative pressure or furtheraway from a source of positive pressure. Conversely, the term “upstream”implies something relatively further away from a source of negativepressure or closer to a source of positive pressure. Similarly, it maybe convenient to describe certain features in terms of fluid “inlet” or“outlet” in such a frame of reference. This orientation is generallypresumed for purposes of describing various features and componentsherein. However, the fluid path may also be reversed in someapplications (such as by substituting a positive-pressure source for anegative-pressure source) and this descriptive convention should not beconstrued as a limiting convention.

In some embodiments, the controller 120 may receive and process datafrom one or more sensors, such as the first sensor 125. The controller120 may also control the operation of one or more components of thetherapy system 100 to manage the pressure delivered to the tissueinterface 135. In some embodiments, controller 120 may include an inputfor receiving a desired target pressure, and may be programmed forprocessing data relating to the setting and inputting of the targetpressure to be applied to the tissue interface 135. In some exampleembodiments, the target pressure may be a fixed pressure value set by anoperator as the target negative pressure desired for therapy at a tissuesite and then provided as input to the controller 120. The targetpressure may vary from tissue site to tissue site based on the type oftissue forming a tissue site, the type of injury or wound (if any), themedical condition of the patient, and the preference of the attendingphysician. After selecting a desired target pressure, the controller 120can operate the negative-pressure source 105 in one or more controlmodes based on the target pressure, and may receive feedback from one ormore sensors to maintain the target pressure at the tissue interface135. In some embodiments, the manifold 405 may have distinct pressurezones, and different target pressures and control modes may be appliedto different pressure zones.

The systems, apparatuses, and methods described herein may providesignificant advantages. For example, in addition to benefits of increasedevelopment of granulation tissue and reduce healing times of incisions,system 100 can also reduce edema and bruising in a broader area adjacentto an incision. The dressing 110 can reduce stress on an incision andmaximize coverage area of articulating joints, while still allowing forrange of motion. The dressing 110 can also be beneficial for managingedema and bruising of tissue sites without an incision or open wound,such as a sprain. In some embodiments, the features of the dressing 110may allow an area to be treated for up to 14 days without changing thedressing 110.

While shown in a few illustrative embodiments, a person having ordinaryskill in the art will recognize that the systems, apparatuses, andmethods described herein are susceptible to various changes andmodifications that fall within the scope of the appended claims.Moreover, descriptions of various alternatives using terms such as “or”do not require mutual exclusivity unless clearly required by thecontext, and the indefinite articles “a” or “an” do not limit thesubject to a single instance unless clearly required by the context.Components may be also be combined or eliminated in variousconfigurations for purposes of sale, manufacture, assembly, or use. Forexample, in some configurations the dressing 110, the container 115, orboth may be eliminated or separated from other components formanufacture or sale. In other example configurations, the controller 120may also be manufactured, configured, assembled, or sold independentlyof other components.

The appended claims set forth novel and inventive aspects of the subjectmatter described above, but the claims may also encompass additionalsubject matter not specifically recited in detail. For example, certainfeatures, elements, or aspects may be omitted from the claims if notnecessary to distinguish the novel and inventive features from what isalready known to a person having ordinary skill in the art. Features,elements, and aspects described in the context of some embodiments mayalso be omitted, combined, or replaced by alternative features servingthe same, equivalent, or similar purpose without departing from thescope of the invention defined by the appended claims.

1. A dressing for treating an area around an articulating joint withnegative pressure, the dressing comprising: an attachment device havinga treatment aperture; a manifold comprising a stem, a first arm joinedto the stem, and a second arm joined to the stem, the manifold at leastpartially exposed through the treatment aperture; a cover disposed overthe manifold and coupled to the attachment device around the manifold;and an adhesive on the attachment device configured to bond to the areaaround the articulating joint.
 2. The dressing of claim 1, wherein thefirst arm has a greater span than the second arm.
 3. The dressing ofclaim 1, wherein: the first arm has a first span; the second arm has asecond span; and a ratio of the first span to the second span is in arange of 1.2 to 3.4.
 4. The dressing of claim 1, wherein: the first armhas a first span; the second arm has a second span; and a ratio of thefirst span to the second span is in a range of 1.2 to 1.6.
 5. Thedressing of claim 1, wherein the first arm and the second arm flare awayfrom the stem.
 6. The dressing of claim 1, wherein the first arm and thesecond arm comprise converging edges.
 7. The dressing of claim 1,wherein the stem, the first arm, and the second arm define biconcaveedges.
 8. The dressing of claim 1, wherein the manifold comprises a facethat is biconcave.
 9. The dressing of claim 1, wherein the manifold hasa line of symmetry through the stem.
 10. The dressing of claim 1,wherein: the manifold has a line of symmetry through the stem; and thefirst arm and the second arm define a void adjacent to each side of thestem.
 11. The dressing of claim 1, wherein: the manifold has an edgebounding the first arm and the second arm; and a portion of the edgebounding the first arm and the second arm converges toward the stem todefine a concave void adjacent to each side of the stem.
 12. Thedressing of claim 1, wherein the stem comprises flexibility notches. 13.The dressing of claim 1, wherein the first arm and the second armcomprise flexibility notches.
 14. The dressing of claim 1, furthercomprising a dressing interface fluidly coupled to the first arm throughthe cover.
 15. The dressing of claim 1, wherein the manifold comprisesfoam.
 16. The dressing of claim 1, further comprising a comfort layercoupled to the manifold, the comfort layer at least partially exposedthrough the treatment aperture.
 17. The dressing of claim 1, wherein:the first arm and the second arm comprise a first foam; the stemcomprises a second foam; and the first foam has a different density thanthe second foam.
 18. The dressing of claim 1, wherein the stem isfluidly isolated from at least one of the first arm and the second arm.19. The dressing of claim 1, wherein the adhesive is disposed in aborder of the attachment device.
 20. The dressing of claim 1, whereinthe adhesive covers at least a portion of the attachment device oppositethe first arm and the second arm.
 21. The dressing of claim 1, whereinthe adhesive covers about 50% of the attachment device opposite thefirst arm and the second arm.
 22. A method of treating edema around anarticulating joint of a limb, the method comprising: applying thedressing of claim 1 so that the stem is disposed over the articulatingjoint; wrapping the first arm around a proximal portion of the limb;wrapping the second arm around a distal portion of the limb; fluidlycoupling a negative-pressure source to the manifold; and applyingnegative-pressure from the negative-pressure source.
 23. A dressing fortreating an area of tissue with negative pressure, the dressingcomprising: a sealing ring having a treatment aperture; a cover having aperimeter coupled to the sealing ring; and a manifold disposed betweenthe sealing ring and the cover and at least partially exposed throughthe treatment aperture; wherein the manifold comprises: a first portionconfigured to be disposed over an articulating surface of a limb; asecond portion configured to be at least partially wrapped around aproximal portion of the limb; and a third portion configured to be atleast partially wrapped around a distal portion of the limb.
 24. Thedressing of claim 23, wherein the second portion and the third portionflare away from the first portion.
 25. The dressing of claim 23, whereinthe second portion and the third portion comprise converging edges. 26.The dressing of claim 23, wherein the first portion, the second portion,and the third portion define biconcave edges.
 27. A method of treatingedema around an articulating joint of a limb, the method comprising:applying the dressing of claim 23 so that the first portion of themanifold is disposed over the articulating joint; wrapping the secondportion around a proximal portion of the limb; wrapping the thirdportion around a distal portion of the limb; fluidly coupling anegative-pressure source to the manifold; and applying negative-pressurefrom the negative-pressure source; wherein the dressing allows thearticulating joint to articulate.
 28. The method of claim 27, whereinthe articulating joint is a knee.
 29. The method of claim 27, whereinthe articulating joint is an elbow.
 30. A dressing for treating an areawith an incision on an articulating joint, the dressing comprising: anattachment device having a treatment aperture; a manifold having a firstportion configured to cover the incision and a second portion configuredto cover the area around the articulating joint; and a cover disposedover the manifold and coupled to the attachment device around themanifold; wherein the manifold is at least partially exposed through thetreatment aperture.
 31. The dressing of claim 30, wherein the manifoldis a generalized cylinder having a biconcave face.
 32. The dressing ofclaim 31, wherein the biconcave face has contoured extremities. 33.(canceled)